Hi Scott My 2 cents. I guess you could advertise two /44s through eBGP sessions (one per each site). In case one uplink goes down, you would advertise locally generated /44 and /44 route learned through iBGP from another site. Basically, router may advertise /44 from the neighboring site as soon as upstream ISP withdraws this route (we can't advertise iBGP learned route to ISP cause we have a best route through it). You could configure a higher LOCAL_PREF for eBGP sessions to make sure that inter site traffic is not going through the backdoor link in normal scenario. I assume that return traffic won't go through the backdoor connection as well, unless one of your uplink goes down. Also I would use SoO community to prevent possible routing loops. One more thing. I heard that there're some issues related to IPv6 multihoming. I guess you might check out existing RFCs for more details.
/ET On 9/19/13 11:13 PM, "Scott Voll" <[email protected]> wrote: >I'm trying to wrap my head around the best way to setup BGP with IPv6 > >We currently have two different ISP's connected to two different sites. > then we run iBGP between the sites. > >so in an IPv4 world have a class C at each location. then at each >location >my Firewalls NAT to the correct Class C as they exit my network. > >This way if the link between sites go down I'm not black holing the other >sites because each site has it's own Class C it's announcing. > >Now if I have a single /40 and I'm subnetting it per location(eg /44), but >all the other sites behind these sites are within that /40 how do I make >sure I don't end up blackholing the other site(s)? Does that make sense? > Do I need to announce a /44 from each site? if so, that will kill my >meshed network(internal) if one site(external) goes down, or the WAN links >go down. > >Thanks for any ideas. Is there a best practice for this kind of setup? > >TIA > >Scott >_______________________________________________ >cisco-nsp mailing list [email protected] >https://puck.nether.net/mailman/listinfo/cisco-nsp >archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
